Correlation between Ki‐67 index and some clinical aspects of acoustic neuromas (vestibular schwannomas)

Abstract

Evaluation of the proliferation activity of neuromas has a practical meaning when there are doubts about the complete resection of the tumor. Evaluation of the clinical aspects connected with increased proliferation activity may have a much broader application. The aim of this study was to correlate selected clinical and radiologic aspects of vestibular schwannomas with the results of the Ki-67 index. The studied group included 23 males and 20 females. Unilateral neuromas were stated in 38 cases (mean age, 52.2 years) and bilateral tumors in 5 cases (mean age, 44.2 years). The immunohistochemical tests (Ki-67) were performed on the specimens preserved in formalin and stored in paraffin. The Ki-67 index was estimated in a semiquantitative study. The mean value of Ki-67 index was 1.86%. In case of unilateral neuromas (n = 38), the average Ki-67 index was 1.74%. In 5 cases of bilateral tumors, the index amounted to 2.79% (P = 0.278). No significant correlation was found by comparing the value of the Ki-67 index with the age of patients (P = 0.410: r = 0.128). Significant differences in the value of the Ki-67 index were noted in the sub-groups of tumors that were evaluated radiologically as growing and stable. The mean value of Ki-67 index was 3.17% in the first subgroup; in stable neuromas, it was significantly lower, amounting to 1.11% (P = 0.020). Such results may confirm that the growth rate of vestibular schwannomas varies and may explain the difficulties in estimating the growth of neuromas on the basis of clinical aspects only.

Neurotransmitters Involved in the Opioid Regulation of Prolactin Secretion at the End of Pregnancy in Rats

“…Numerous observations indicate that EOP and opiate agonists suppress the activity of TIDA neurons by activation of µ- and/or ĸ-receptors [49, 50, 51, 52], thereby increasing the prolactin secretion [53, 54]. In the present study, we did not find an inverse correlation between prolactin levels and DOPAC/DA ratio after DAMGO or β-END administration.…”

The Molecular Biology of Vestibular Schwannomas: Dissecting the Pathogenic Process at the Molecular Level

“…An increase in Ki-67, which is an index of nuclear proliferation, was shown to correlate with the growth of solid schwannomas on MRI (93). Higher rates of tumor recurrence have also been suggested in tumors with an increased rate of nuclear proliferation and mitotic indexes, although the supporting data for this claim are not conclusive (94).…”

The VEGF/VEGF-R Axis in Sporadic Vestibular Schwannomas Correlates with Irradiation and Disease Recurrence

“…One possible explanation for these conflicting literature reports is that the assessment of proliferation indexes can be influenced by the point of time when the operation is performed and the tissue becomes available for analysis, since many VS do not grow continuously but can remain stable over a long period of time [2]. Niemczyk et al [34] have reported in a study of 12 VS that the group of tumors which had been shown to grow at the time of surgical removal had a higher proliferation index than the group of stable (nongrowing) tumors. A further factor that may influence the value of the assessed Ki-67 index is the exact location of the biopsy taken.…”